If you apply a rom or theme - backup first!
If you don't know how to backup...Stop until you do.
hint: I name my backups like this: sg6.0_20100428 or ss4.2_20100626 to easily find them later. rom and date.
Have a Problem, Click here to Visit the Rescue Squad
Just to git rid of extra baggage. I backed my SD card up to my hard drive then erased it. I copied my pictures and music back on and let the Droid re-index/re-thumbnail everything. i filled in some blanks that some of my apps needed by restoring their data and let the Droid re-build the rest.
Turns out I had about 1 GB of extra crap following me around. Must have been all the apps I experimented with when I first got the phone. I thought only Microsoft had bad un-installers
Anyhow, I have the new ROM tweaked the way I want it so my next stop is another nandriod backup I'll call "The Happy Beast." Then I'll see about a theme.
I have made pseudo themes (before I even rooted and installed a ROM)
Folder Organizer (free version) - lets me change the icons of Apps and Folders.
Launcher Pro (free version) - lets me do up to a 10 by 10 grid for very granular placement of icons and gives me control over the icon tray at the bottom of the screen and the status bar at the top.
Combine that with some custom icons and you can do pretty well for a theme.
I'll try to attach a screenshot (the screenshot required root but nothing everything on the display can be accomplished without rooting)